The present invention relates broadly to dental materials useful in restorative and preventive dental work. Dental materials of the invention provide hardenable compositions having color-changing capability upon exposure to actinic radiation.
Sealants are frequently used to deter dental caries that occur due to accumulation of caries-producing microorganisms in a patient""s dentition. The areas in the topography of a dentition that are most desirably treated using a sealant are what are commonly referred to as pits and fissures. Sealants are used to fill pits and fissures to achieve a smooth topography, to avoid microorganism accumulation yet not be detrimental to mastication capability.
U.S. Pat. No. 4,150,012 teaches a dental composition made from a two-part system, where each of the two parts comprise a polymerizable resin and an opaquing filler; however, the first container comprises a catalyst, while the second container comprises an accelerator reactive with the catalyst in the first container.
The dental material is chemically cured (via redox reaction) and provides an opaque dental material when cured.
U.S. Pat. No. 5,583,178 provides a composition for indicating visually a cure point of a hydrosilation-curable composition (e.g., a silicone composition) via a color change. A cure indicating dye is added to the curable composition to provide a visual indication of the extent of the hydrosilation reaction (e.g., extent of the crosslinking reaction) .
U.S. Pat. No. 5,596,025 provides a dental impression material whose cure can be monitored visually, comprising: 1) a curable silicone polymer; 2) a crosslinker compound containing silicon-bonded hydrogen groups; 3) a hydrosilation catalyst; and 4) one or more cure-indicating dyes that exhibit a color change in the presence of a silicon-bonded hydrogen compound and a hydrosilation catalyst.
Conventional dental sealants are provided in either a clear composition or a composition comprising titanium dioxide for imparting a white color. Placement of dental sealant material on teeth surfaces is often difficult due to the similarity in color of the composition and the teeth, or the lack of color in the composition. Since it is important that sealant material is placed accurately in or on the desired pits and fissures to achieve the benefit of minimizing bacterial accumulation, it would be very beneficial to provide a composition that initially, is easily seen and discernible from the teeth surface, yet upon curing, can advantageously change to a tooth-like color to closely match that of the tooth surface(s).
The present invention provides a hardenable dental composition having color-changing capability to aid a practitioner in properly placing desired amounts of composition in and on areas of dentition. Methods of using a color-changing dental composition are also provided.
The compositions of the invention have an initial color prior to exposure to actinic radiation and have a different, final color subsequent to exposure to actinic radiation. The compositions are capable of undergoing a change in color of xcex94E* greater than about 10.
In one aspect of the invention, the compositions of the invention have a final color that is tooth-like, or matches the color of naturally occurring dentition.
In another aspect of the invention, a dye or a combination of dyes can be used to impart a desired initial color to the composition.
In a further aspect of the invention, the compositions and methods of the invention are useful as sealants, restoratives and prostheses.
As used herein the following terms are intended to have the following definitions:
xe2x80x9chardenablexe2x80x9d is descriptive of a material that can be cured or solidified e.g., by heating to remove solvent, heating to cause polymerization, chemical cross-linking, radiation-induced polymerization or crosslinking, or the like;
xe2x80x9cphoto-bleach(able)xe2x80x9d means a loss of color upon exposure to actinic radiation;
xe2x80x9chardenerxe2x80x9d means a system that initiates hardening of a resin, and can be used synonymously with xe2x80x9cinitiator system.xe2x80x9d